JP2015232551A - Gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas sensor capable of suppressing an electrical connection failure between a connection terminal and an electrode pad.SOLUTION: A gas sensor element 7 of an air-fuel ratio sensor 1 includes a plurality of through holes 163, 162, 161 that are formed in tip regions of electrode pads 25, 27, 29 to be their connection destinations on an insulation substrate 97. In the gas sensor element 7, no through hole is formed in a rear end region and a central region of the electrode pads 25, 27, 29 in a longitudinal direction. Since sites of the electrode pads 25, 27, 29 other than the tip region have large areas, it is easy to bring a connection terminal 15 into contact with the sites of the electrode pads 25, 27, 29 other than the tip region. This can prevent the connection terminal 15 from coming into contact with the through holes 163, 162, 161, and further suppress an electrical connection failure between the connection terminal 15 and the electrode pads 25, 27, 29.

Description

  The present invention relates to a gas sensor including a cell having a solid electrolyte body and a pair of electrode portions, a plate-shaped insulating substrate stacked on the cell, and a plurality of electrode pad portions disposed on the outer surface of the insulating substrate.

  As a gas sensor for detecting a specific gas component in a measurement target gas, for example, a plate shape extending in the longitudinal direction, a cell that outputs a sensor signal corresponding to the specific gas component, and a plate shape stacked on the cell are used. An insulating substrate formed of an insulating material and having a plurality of through holes penetrating in the thickness direction on the rear end side and having conductors disposed therein, and a plurality of through holes disposed on the outer surface of the insulating substrate (details) Some of them include a plurality of electrode pad portions that are connected to the cell via internal conductors and output sensor signals to the outside.

  And as a cell, for example, a frame member made of a plate-shaped insulating material extending in the longitudinal direction and having a hollow portion on the tip side, a solid electrolyte body disposed in the hollow portion, and an outer surface of the solid electrolyte body There is a buried type cell including a pair of electrode portions formed on the substrate and a pair of lead portions connected to the electrode portions and extending in the longitudinal direction (Patent Document 1).

By employing such a buried cell, the amount of solid electrolyte used can be reduced, and the manufacturing cost of the gas sensor can be reduced.
Moreover, as a gas sensor for detecting a specific gas component in the measurement target gas, in addition to each of the above-described configurations, a plurality of connection terminals connected to the electrode pad part and a state in which the connection terminals are connected to the electrode pad part Some have a metal shell for holding a gas sensor element (Patent Document 1).

Japanese Patent No. 4093784

However, the above conventional gas sensor has a poor electrical connection with the connection terminal connected to the electrode pad portion, and may not output the sensor signal properly.
For example, when the formation positions of the plurality of through holes in the insulating substrate are positions different from each other in the longitudinal direction, the contact position with the connection terminal in any one of the plurality of electrode pad portions is the formation position of the through holes. There is a possibility. As for the arrangement form of the conductor inside the through hole, the conductor is formed on the inner peripheral wall surface of the through hole and the central axis portion in the through hole penetration direction is hollow, or the conductor is inside the through hole. The arrangement | positioning form etc. with which it is filled are mentioned.

  Among these, in the case of a through hole that employs an arrangement form in which the central axis portion is hollow as the conductor arrangement form, when any one of the plurality of connection terminals contacts the electrode pad portion at the through hole formation position In some cases, the contact area between the connection terminal and the electrode pad portion is reduced, and the electrical connection between the connection terminal and the electrode pad portion may be poor.

  On the other hand, not only the through hole adopting the arrangement form in which the central axis portion is hollow as the conductor arrangement form, but also the through hole adopting the arrangement form filled with the conductor, the gas sensor element and the connection terminal In the assembly process, some of the connection terminals may be deformed. Specifically, in the process of assembling the gas sensor element and the connection terminal, when the connection terminal is moved (slid) from the rear end side to the front end side of the outer surface of the gas sensor element, a part of the connection terminal becomes a through hole. The hook connection terminal may be deformed. When such deformation of the connection terminal occurs, there is a possibility that an electrical connection failure (abnormal disconnection) between the connection terminal and the electrode pad portion may occur.

  Then, an object of this invention is to provide the gas sensor which can suppress that the electrical connection of a connection terminal and an electrode pad part becomes defective.

A gas sensor according to one aspect of the present invention includes a gas sensor element, a plurality of connection terminals, and a metal shell, and detects a specific gas component in a measurement target gas.
The gas sensor element includes a cell, an insulating substrate, and a plurality of electrode pad portions.

The cell includes a frame member, a solid electrolyte body, a pair of electrode portions, and a pair of lead portions.
The frame member is made of a plate-shaped insulating material extending in the longitudinal direction, has a hollow portion at the front end side, and has a plurality of first throughs through which conductors are disposed in the rear end side in the thickness direction. Has a hole. The solid electrolyte body is disposed in the hollow portion. The pair of electrode portions are formed on the outer surface of the solid electrolyte body. The pair of lead portions are connected to the electrode portion and the first through hole and extend in the longitudinal direction.

  The insulating substrate is formed of a plate-shaped insulating material laminated on the cell, and has a conductor penetrating in the thickness direction on the rear end side and communicating with the plurality of first through holes. A plurality of second through holes are provided. The plurality of electrode pad portions are connected to the plurality of second through holes arranged on the outer surface of the insulating substrate.

The plurality of connection terminals are connected to the electrode pad portion. The metal shell holds the gas sensor element in a state where the connection terminal is connected to the electrode pad portion.
The plurality of second through holes are formed in the tip region of the electrode pad portion that is the connection destination of each of the insulating substrates.

  In the gas sensor configured as described above, the second through hole is formed in the distal end region of the electrode pad portion, and the second through hole is formed in the rear end region and the central region in the longitudinal direction of the electrode pad portion. Not. Since the electrode pad portion other than the tip region (in other words, one of the rear end region and the central region) occupies a large area, the connection terminal is connected to the electrode pad portion other than the tip side region. It becomes easy to make it contact | abut to a location.

  Thus, since it becomes easy to take the structure which connects with a connection terminal in places other than a front-end | tip area | region among electrode pad parts, it can suppress that a connection terminal contact | abuts with a 2nd through hole, and a connection terminal and an electrode pad It can suppress that electrical connection with a part becomes defective.

  In addition, since the second through hole is formed in the tip region of the electrode pad part, the connecting terminal is connected to the tip from the rear end side of the outer surface of the gas sensor element in the assembly process with the connecting terminal connected to the electrode pad part. When moving (sliding) to the side, the connection terminal does not move on the second through hole. For this reason, it can suppress that a part of connection terminal is caught in a 2nd through hole, and a connection terminal deform | transforms, and the electrical connection defect (disconnection abnormality) of a connection terminal and an electrode pad part accompanying a deformation | transformation of a connection terminal generate | occur | produces. This can be suppressed.

Therefore, according to the gas sensor element of this invention, generation | occurrence | production of the electrical connection failure of an electrode pad part and a connection terminal can be suppressed.
Note that the configuration in which the second through hole is formed in the tip end region of the electrode pad portion has a shorter cell lead portion length than the configuration in which the second through hole is formed in the rear end region of the electrode pad portion. And the amount of noble metal used for the lead portion can be reduced. Thereby, the manufacturing cost of a gas sensor can be reduced.

  Furthermore, as an arrangement form of the conductors inside the first through hole and the second through hole, for example, a conductor is formed on the inner peripheral wall surface of the through hole, and the central axis portion in the through hole penetration direction is hollow. Arrangement forms, arrangement forms in which conductors are filled in through holes, and the like can be mentioned.

In the gas sensor of the present invention, the plurality of electrode pad portions may be arranged through gaps in the width direction of the plate surface of the insulating substrate.
In this case, in the assembly process of the gas sensor element and the connection terminal, when the connection terminal is moved (slid) from the rear end side to the front end side of the outer surface of the gas sensor element, the electrode pad portion is scraped by the connection terminal and the electrode Even if the chip portion of the pad portion is scraped, electrical connection failure (short circuit abnormality) due to conduction between the plurality of electrode pad portions is unlikely to occur.

  That is, when the scrap of the electrode pad portion occurs, the moving direction of the scrap is the longitudinal direction of the plate surface of the insulating substrate, which is the moving direction of the connection terminal, and the width direction of the plate surface of the insulating substrate (in other words, The movement range in the short direction is small. In addition, since the plurality of electrode pad portions are arranged with gaps in the width direction, it is difficult for the plurality of electrode pad portions to be electrically connected to each other due to the scrap.

Therefore, according to the gas sensor of this invention, generation | occurrence | production of the electrical connection failure of an electrode pad part and a connection terminal can be suppressed.
In the gas sensor of the present invention, the plurality of electrode pad portions may be arranged through gaps in the longitudinal direction of the plate surface of the insulating substrate.

  As described above, since the plurality of electrode pad portions are arranged with gaps in the longitudinal direction from each other, the plurality of electrode pad portions are arranged in a state where the distance from each other is increased, and therefore, the plurality of electrode pad portions are formed by cross-linking of some foreign matter. Electrical connection failure (short circuit abnormality) is less likely to occur when the electrode pad portions are electrically connected.

  In addition, when the plurality of electrode pad portions are arranged via the gap in the width direction and the gap in the longitudinal direction, the distance between the electrode pad portions is further increased, so the electrode pad Electrical connection failure (short circuit abnormality) due to conduction between the parts is less likely to occur.

Therefore, according to the gas sensor of the present invention, electrical connection failure (short circuit abnormality) due to conduction between a plurality of electrode pad portions is unlikely to occur.
Next, in the gas sensor of the present invention, the distance between the plurality of first through holes may be 2.3 [mm] or less.

  By arranging a plurality of first through holes according to such a numerical range, the formation region of the first through holes can be reduced, the gas sensor element can be downsized, and the gas sensor can be downsized. Become.

  In addition, in the gas sensor of this invention, since the cell (embedded cell) of the structure by which a solid electrolyte body is arrange | positioned in the hollow part of a frame member is provided as a cell, when forming a 1st through hole in a cell, it is solid. It can be formed on a frame member made of an insulating material instead of the electrolyte body. For this reason, even if the distance between the plurality of first through holes is set to be less than 4.8 [mm], the occurrence of a leakage current (leakage current) between the plurality of first through holes can be suppressed.

  Therefore, according to the present invention, it is possible to suppress the occurrence of leakage current (leakage current) between the plurality of first through holes, and to suppress the current path from the electrode portion of the cell to the electrode pad portion from becoming an abnormal state. it can.

  Next, in the gas sensor of the present invention, the electrode pad portion has a maximum width dimension in the rear end side region from the center point of the second through hole, and a maximum width dimension in the tip side region from the center point of the second through hole. It may be a larger shape.

  That is, since the rear end region of the electrode pad portion from the center point of the second through hole is a contact region with the connection terminal, the electrode pad portion having a large maximum width dimension is connected to the connection terminal. The contact state of is improved.

  Thereby, according to the gas sensor of this invention, generation | occurrence | production of the electrical connection failure of an electrode pad part and a connection terminal can be suppressed.

  According to the gas sensor of the present invention, it is possible to suppress the occurrence of poor electrical connection between the electrode pad portion and the connection terminal.

It is sectional drawing showing the internal structure of an air fuel ratio sensor. It is a perspective view showing the external appearance of a gas sensor element. It is the perspective view which decomposed | disassembled the gas sensor element. It is explanatory drawing showing the arrangement state of the electrode pad in the rear end side of a gas sensor element. It is an expanded sectional view showing the internal structure in the formation region of a through hole among gas sensor elements. It is explanatory drawing regarding the manufacturing method of the molded object of a gas sensor element. It is explanatory drawing which shows the manufacture middle stage of a gas sensor element. It is the test result which measured the insulation resistance between through holes. It is explanatory drawing showing the arrangement state of the electrode pad in the rear end side of the gas sensor element of 2nd Embodiment. It is explanatory drawing showing the arrangement state of the electrode pad in the rear end side of the gas sensor element of 3rd Embodiment.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
In the embodiment described below, an all-range air-fuel ratio sensor (hereinafter also simply referred to as an air-fuel ratio sensor) is taken as an example of an oxygen sensor that is a kind of gas sensor. Specifically, for use in air-fuel ratio feedback control in automobiles and various internal combustion engines, a gas sensor element (detection element) for detecting a specific gas (oxygen) in exhaust gas to be measured is assembled, and the internal combustion engine An air-fuel ratio sensor attached to the exhaust pipe will be described as an example.

[1. First Embodiment]
[1-1. overall structure]
An overall configuration of an air-fuel ratio sensor in which the gas sensor element of the present embodiment is used will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the internal configuration of the air-fuel ratio sensor.

  As shown in FIG. 1, an air-fuel ratio sensor 1 according to the present embodiment includes a cylindrical metal shell 5 having a screw part 3 formed on the outer surface for fixing to an exhaust pipe, and an axis O direction (air-fuel ratio sensor 1 Plate-shaped gas sensor element 7 extending in the longitudinal direction of FIG. 1, a cylindrical ceramic sleeve 9 arranged to surround the circumference of the gas sensor element 7 in the radial direction, and an insertion penetrating in the direction of the axis O An insulating contact member 13 (separator 13) arranged with the inner wall surface of the hole 11 surrounding the rear end of the gas sensor element 7, and five pieces arranged between the gas sensor element 7 and the separator 13 (FIG. 1). , Only two of them are shown).

  As will be described in detail later, the gas sensor element 7 includes a rectangular parallelepiped element main body portion 70 extending in the longitudinal direction and a porous protective layer 17 covering the tip end side of the element main body portion 70. The element main body 70 includes a detection unit 90 that detects a specific gas contained in the measurement target gas on the tip side. In addition, the gas sensor element 7 has electrode pads 25 on the first main surface 21 and the second main surface 23 that are in a positional relationship of the front and back of the outer surface on the rear end side (upper side in FIG. 1: rear end portion in the longitudinal direction). 27, 29, 31, and 33 (see FIGS. 2 and 3 for details) are formed.

  The connection terminal 15 is electrically connected to the electrode pads 25, 27, 29, 31, and 33 of the gas sensor element 7, and is also electrically connected to a lead wire 35 disposed inside the sensor from the outside. Thus, a current path for a current flowing between the external device to which the lead wire 35 is connected and the electrode pads 25, 27, 29, 31, 33 is formed.

  The metal shell 5 has a through-hole 37 that penetrates in the direction of the axis O, and has a substantially cylindrical shape having a shelf 39 that protrudes radially inward of the through-hole 37. In the metal shell 5, the detection unit 90 is disposed on the front end side of the through hole 37, and the electrode pads 25, 27, 29, 31, 33 are disposed on the rear end side of the through hole 37. Thus, the gas sensor element 7 inserted through the through hole 37 is held.

  Further, inside the through hole 37 of the metal shell 5, an annular ceramic holder 41, a talc ring 43, a talc ring 45, and the above-described ceramic sleeve 9 are provided so as to surround the periphery of the gas sensor element 7 in the radial direction. They are laminated in order from the front end side to the rear end side.

  A caulking packing 49 is disposed between the ceramic sleeve 9 and the rear end portion 47 of the metal shell 5. On the other hand, between the ceramic holder 41 and the shelf 39 of the metal shell 5, a talc ring 43 or the like. A metal holder 51 for holding the ceramic holder 41 is arranged. Note that the rear end portion 47 of the metal shell 5 is crimped so as to press the ceramic sleeve 9 toward the front end side via a crimping packing 49.

  Further, a metal double protector 55 (for example, stainless steel) covering the protruding portion of the gas sensor element 7 is attached to the outer periphery of the distal end portion 53 of the metal shell 5 by welding or the like.

  On the other hand, an outer cylinder 57 is fixed to the outer periphery on the rear end side of the metal shell 5. Further, in the opening on the rear end side of the outer cylinder 57, five lead wires 35 (three are shown in FIG. 1) electrically connected to the electrode pads 25, 27, 29, 31, 33, respectively. A grommet 61 in which a lead wire insertion hole 59 is inserted is disposed.

A flange 63 is formed on the outer periphery of the separator 13, and the flange 63 is fixed to the outer cylinder 57 via a holding member 65.
[1-2. Configuration of gas sensor element]
Next, the structure of the gas sensor element 7 which is the principal part of this embodiment is demonstrated in detail based on FIGS.

FIG. 2 is a perspective view showing the appearance of the gas sensor element 7.
As shown in FIG. 2, the gas sensor element 7 is a long plate material extending in the longitudinal direction (Y-axis direction). In FIG. 2, the longitudinal direction is along the direction of the axis O of the gas sensor. 2 is a stacking direction perpendicular to the longitudinal direction, and the X-axis direction is a width direction perpendicular to the longitudinal direction and the stacking direction.

  The gas sensor element 7 includes a rectangular parallelepiped element main body 70 extending in the longitudinal direction, and a porous protective layer 17 that covers the tip side (lower side in FIG. 2) of the element main body 70. The element body 70 is configured by laminating a plate-like element portion 71 extending in the longitudinal direction and a plate-like heater 73 extending in the longitudinal direction (see FIG. 3). The element main body 70 includes a detection unit 90 that detects a specific gas contained in the measurement target gas on the tip side. The protective layer 17 is made of porous alumina and covers at least the front end surface 127 and the side surfaces (the first main surface 21, the second main surface 23, the first main surface 21) of the element body 70 so as to cover at least the detection unit 90. Provided on side 111, second side 113).

FIG. 3 is an exploded perspective view of the gas sensor element 7. In addition, illustration of the protective layer 17 is abbreviate | omitted in FIG.
The element main body 70 of the gas sensor element 7 is disposed on one side in the stacking direction (upper side in FIG. 3) and extends in the longitudinal direction as shown in FIG. A plate-like heater 73 disposed on the opposite side (back side) of the portion 71 and extending in the longitudinal direction.

Among these, the element unit 71 includes an oxygen concentration battery cell 81, an oxygen pump cell 89, an insulating spacer 93, and an insulating substrate 97.
The oxygen concentration battery cell 81 includes an insulating member 76, a solid electrolyte body 75, a porous electrode 77, a lead portion 77a, a porous electrode 79, and a lead portion 79a.

  The insulating member 76 is a plate-shaped member mainly composed of alumina, and includes a through hole 76a penetrating in the thickness direction. The solid electrolyte body 75 is disposed in the through hole 76 a of the insulating member 76. The pair of porous electrodes 77 and 79 are arranged on the front and back surfaces of the solid electrolyte body 75 so as to sandwich the solid electrolyte body 75.

That is, the oxygen concentration battery cell 81 is an embedded type cell having a configuration in which the solid electrolyte body 75 is embedded in the through hole 76 a of the insulating member 76.
One end of the lead portion 77a is connected to the porous electrode 77, and is disposed so as to extend in the longitudinal direction (left and right direction in FIG. 3) of the gas sensor element 7 (element main body portion 70). One end of the lead portion 79a is connected to the porous electrode 79, and is disposed so as to extend in the longitudinal direction of the gas sensor element 7 (element main body portion 70) (left and right direction in FIG. 3).

The oxygen pump cell 89 includes an insulating member 84, a solid electrolyte body 83, a porous electrode 85, a lead portion 85a, a porous electrode 87, and a lead portion 87a.
The insulating member 84 is a plate-shaped member mainly composed of alumina, and includes a through hole 84a penetrating in the thickness direction. The solid electrolyte body 83 is disposed in the through hole 84 a of the insulating member 84. The pair of porous electrodes 85 and 87 are disposed on the front and back surfaces of the solid electrolyte body 83 so as to sandwich the solid electrolyte body 83.

That is, the oxygen pump cell 89 is an embedded type cell having a configuration in which the solid electrolyte body 83 is embedded in the through hole 84 a of the insulating member 84.
One end of the lead portion 85a is connected to the porous electrode 85, and is disposed so as to extend in the longitudinal direction of the gas sensor element 7 (element main body portion 70) (left and right direction in FIG. 3). One end of the lead portion 87a is connected to the porous electrode 87, and is disposed so as to extend in the longitudinal direction of the gas sensor element 7 (element main body portion 70) (left and right direction in FIG. 3).

  The solid electrolyte bodies 75 and 83 are formed of zirconia in which yttria is dissolved as a stabilizer. The solid electrolyte body 75 has a configuration in which a cross-sectional area in a plane perpendicular to the stacking direction is larger than that of the solid electrolyte body 83.

The porous electrodes 77, 79, 85, 87 and the lead portions 77a, 79a, 85a, 87a are mainly formed of Pt.
The insulating spacer 93 is a plate-shaped member mainly made of alumina, and includes a hollow gas measuring chamber 91. The insulating spacer 93 is stacked between the oxygen concentration battery cell 81 and the oxygen pump cell 89. Inside the gas measurement chamber 91, one porous electrode 77 of the oxygen concentration battery cell 81 and one porous electrode 87 of the oxygen pump cell 89 are disposed so as to be exposed.

  Two gas introduction portions 94 serving as intake ports for exhaust gas (measurement target gas) are formed on the side surface of the element portion 71 (side surface of the insulating spacer 93). The gas introduction portion 94 communicates with the gas measurement chamber 91. doing. In each path from the two gas introduction portions 94 to the gas measurement chamber 91, a diffusion rate controlling portion 95 is formed. The diffusion rate controlling unit 95 is made of, for example, a porous body made of alumina or the like, and performs rate limiting when the measurement target gas flows into the gas measurement chamber 91. The diffusion control unit 95 is provided in a state where a part thereof is exposed from the gas introduction unit 94.

  That is, in this gas sensor element 7, the gas introduction part 94 is formed in two different directions on the outermost surface of the element body part 70, and the diffusion rate controlling part 95 is exposed in two different directions. .

  The insulating substrate 97 is a plate-shaped member mainly made of alumina, and includes a space portion 97a penetrating in the thickness direction. In the space portion 97 a of the insulating substrate 97, a ventilation portion 99 made of a porous body similar to the diffusion rate controlling portion 95 is embedded. The ventilation part 99 exposes the porous electrode 85 of the oxygen pump cell 89 to the measurement target gas.

  The gas measurement chamber 91 is formed so as to be located on the distal end side (left side in FIG. 3) of the element main body portion 70 (specifically, the element portion 71). Of the longitudinal direction of the element unit 71, the region where the gas measurement chamber 91 is formed and the region closer to the tip than the gas measurement chamber 91 are provided as a detection unit 90 for detecting oxygen.

On the other hand, the heater 73 is formed by sandwiching a heating resistor pattern 105 mainly composed of Pt between insulating substrates 101 and 103 mainly composed of alumina.
In such a gas sensor element 7, three electrode pads 25, 27, and 29 are formed on the rear end side (right side in FIG. 3) of the first main surface 21, and two electrodes are formed on the rear end side of the second main surface 23. Electrode pads 31 and 33 are formed.

  Among these, one electrode pad 29 (the right electrode pad in FIG. 2) on the first main surface 21 has a through hole 161 provided in the insulating substrate 97 and a through hole 165 provided in the insulating member 84 as shown in FIG. , And electrically connected to the porous electrode 77 of the oxygen concentration battery cell 81 through the through hole 171 provided in the insulating spacer 93 and the lead portion 77a. The electrode pad 29 is also electrically connected to the porous electrode 87 of the oxygen pump cell 89 through a through hole 161 provided in the insulating substrate 97, a through hole 165 provided in the insulating member 84, and a lead portion 87a. The Therefore, the porous electrode 77 and the porous electrode 87 are electrically connected at the same potential.

  In each through hole (through holes 161, 165, etc.), a conductor is disposed inside. As for the arrangement form of the conductor inside the through hole, the conductor is formed on the inner peripheral wall surface of the through hole and the central axis portion in the through hole penetration direction is hollow, or the conductor is inside the through hole. The arrangement | positioning form etc. with which it is filled are mentioned.

  Further, as shown in FIG. 3, the electrode pad 27 (center electrode pad in FIG. 2) is a through hole 162 provided in the insulating substrate 97, a through hole 166 provided in the insulating member 84, and a through hole provided in the insulating spacer 93. 172, electrically connected to the porous electrode 79 of the oxygen concentration battery cell 81 through the through hole 176 provided in the insulating member 76 and the lead portion 79a. Further, as shown in FIG. 3, the electrode pad 25 (left electrode pad in FIG. 2) is electrically connected to the porous electrode 85 of the oxygen pump cell 89 through a through hole 163 and a lead portion 85a provided in the insulating substrate 97. It is connected to the.

  Further, as shown in FIG. 3, the electrode pads 31 and 33 are electrically connected to both ends of the heating resistor pattern 105 through through holes 181 and 182 provided in the insulating substrate 103.

  Returning to FIG. 2, the gas sensor element 7 having the above-described configuration is a long, substantially rectangular parallelepiped-shaped plate member, and therefore, along the longitudinal direction (Y direction in FIG. 2) at the corner portion on the outer peripheral side in the radial direction. 4 sides (longitudinal ridge lines) H1, H2, H3, and H4.

  Specifically, the gas sensor element 7 is connected to the first main surface 21 and the second main surface 23 and the first main surface 21 and the second main surface 23 as four outer peripheral walls extending along the longitudinal direction of the gas sensor element 7. The first side surface 111 and the second side surface 113 are provided. The first side H1 that is a ridge line between the first main surface 21 and the first side surface 111, the second side H2 that is a ridge line between the first main surface 21 and the second side surface 113, and the second A third side H3 that is a ridge line between the main surface 23 and the second side surface 113 and a fourth side H4 that is a ridge line between the second main surface 23 and the first side surface 111 are provided.

A rear end surface 129 perpendicular to the longitudinal direction is formed on the rear end side (upper side in FIG. 2) of the gas sensor element 7.
[1-3. Electrode pads and through holes]
Next, the electrode pads 25, 27, 29 and the through holes of the gas sensor element 7 will be described.

FIG. 4 is an explanatory diagram showing the arrangement state of the electrode pads 25, 27, 29 on the rear end side of the gas sensor element 7.
The electrode pad 25, the electrode pad 27, and the electrode pad 29 are formed on the first main surface 21 of the gas sensor element 7 so as to be connected to the through holes 163, 162, and 161 in the tip end region (left side in FIG. 4), respectively. ing. In other words, the plurality of through holes 163, 162, 161 are formed in the tip regions of the electrode pads 25, 27, 29 that are the connection destinations of the insulating substrate 97.

  In the gas sensor element 7 configured as described above, through holes 163, 162, 161 are formed in the tip region of the electrode pads 25, 27, 29, and the rear end of the electrode pads 25, 27, 29 in the longitudinal direction is formed. Through holes 163, 162, and 161 are not formed in the region and the central region. In addition, the electrode pad 25, 27, 29 has a portion other than the tip region (in other words, any one of the rear end region and the central region) occupies a large area. , 29 can be easily brought into contact with a portion other than the tip side region.

  Thus, since it becomes easy to take the structure which connects with the connection terminal 15 in locations other than a front-end | tip area | region among electrode pads 25, 27, and 29, the connection terminal 15 contacts the through holes 163, 162, and 161. It is possible to suppress the electrical connection between the connection terminal 15 and the electrode pads 25, 27, 29.

  Further, in the gas sensor element 7 configured in this way, in the assembly process with the connection terminal 15 connected to the electrode pads 25, 27, and 29, the connection terminal 15 is moved from the rear end side to the front end side of the outer surface of the gas sensor element 7. When moving (sliding), the connection terminal 15 does not move over the through holes 163, 162, 161. For this reason, it can suppress that a part of connection terminal 15 is caught in the through holes 163, 162, 161 and the connection terminal 15 is deformed, and the connection terminal 15 and the electrode pads 25, 27, 29 accompanying the deformation of the connection terminal 15 are prevented. Occurrence of poor electrical connection (abnormal disconnection) can be suppressed.

  Next, in the gas sensor element 7, the plurality of electrode pads 25, 27, and 29 are arranged via gaps in the width direction (vertical direction in FIG. 4) of the plate surface (first main surface 21) of the insulating substrate 97. ing.

  Specifically, the electrode pad 25 and the electrode pad 27 are arranged via a gap Cw1 in the width direction, and the electrode pad 27 and the electrode pad 29 are arranged via a gap Cw2 in the width direction. .

  With this configuration, when the connection terminal 15 is moved (slid) from the rear end side to the front end side of the outer surface of the gas sensor element 7 in the assembly process of the gas sensor element 7 and the connection terminal 15, the connection terminal 15, even if the electrode pads 25, 27, and 29 are cut and scraps are generated, short-circuit abnormality between the electrode pads 25, 27, and 29 is less likely to occur.

  That is, when the scraps of the electrode pads 25, 27, and 29 are generated, the movement direction of the scraps is the longitudinal direction of the first main surface 21 of the insulating substrate 97 that is the movement direction of the connection terminal 15 (the horizontal direction in FIG. 4). Thus, the range of movement of the first main surface 21 of the insulating substrate 97 in the width direction (vertical direction in FIG. 4) is small. Since the electrode pads 25, 27, and 29 are disposed with a gap in the width direction, it is difficult for the electrode pads 25, 27, and 29 to be electrically connected to each other due to the shavings. , 29 are electrically connected to each other, so that poor electrical connection (short circuit abnormality) is less likely to occur.

  Next, the electrode pads 25, 27, and 29 have the maximum width dimensions Wr 1, Wr 2, and Wr 3 in the rear end side regions from the center points of the through holes 163, 162, and 161, respectively. The shape is larger than the maximum width dimensions Wf1, Wf2, Wf3 of the tip side region from the point.

  That is, the rear end region of the electrode pads 25, 27, and 29 with respect to the center point of the through holes 163, 162, and 161 serves as a contact region with the connection terminal 15. Therefore, the maximum width dimensions Wr1, Wr2, Wr3. The electrode pads 25, 27, and 29 that are secured to have a good contact state with the connection terminal 15.

  Next, in the gas sensor element 7, the distance between the plurality of through holes 163, 162, 161 is 2.3 [mm] or less. Specifically, the distance L1 between the through hole 163 and the through hole 162 is 2.3 [mm], and the distance L2 between the through hole 162 and the through hole 161 is 2.3 [mm].

FIG. 5 shows an enlarged cross-sectional view showing the internal structure of the gas sensor element 7 in the through hole formation region.
By arranging the through holes 163, 162, 161 so that the distance between the plurality of through holes 163, 162, 161 is 2.3 mm or less, the through holes 163, 162, 161 are formed. The area can be reduced, and the gas sensor element 7 can be downsized.

  Since the gas sensor element 7 includes embedded cells as the oxygen concentration battery cell 81 and the oxygen pump cell 89, when the through hole is formed in the cell, it is formed not in the solid electrolyte body but in the insulating member 76 and the insulating member 84. it can. For this reason, even if the distance between the plurality of through-holes 165 and 166 is set to less than 4.8 [mm], the leakage current (leakage) between the plurality of through-holes 165 and 166 via the solid electrolyte bodies 83 and 75. (Current) can be suppressed.

[1-4. Manufacturing method of gas sensor]
A method for manufacturing the air-fuel ratio sensor 1 of the present embodiment will be described with reference to FIGS.
FIG. 6 is an explanatory diagram relating to a method for manufacturing the molded body 141 of the gas sensor element, and FIG. 7 is an explanatory diagram showing a stage in the middle of manufacturing the gas sensor element.

  When manufacturing the gas sensor element 7, first, various laminated materials as materials of the known gas sensor element 7, that is, an unfired solid electrolyte sheet that becomes the solid electrolyte bodies 75 and 83 of the element portion 71, and an insulating member of the element portion 71. 76, the insulating member 84, the unsintered insulating sheet to be the insulating substrate 97, the unsintered insulating sheets to be the insulating substrates 101 and 103 of the heater 73, and the like are laminated to obtain an uncompressed laminate. In this non-bonded laminate, unfired electrode pads to be the electrode pads 25, 27, 29, 31, 33 are formed.

  Among these, for example, when forming an unfired solid electrolyte sheet, first, alumina powder or butyral resin is added to ceramic powder mainly composed of zirconia, and a mixed solvent (toluene and methyl ethyl ketone) is further mixed. To produce a slurry. The slurry is made into a sheet by the doctor blade method, and the mixed solvent is volatilized to produce an unfired solid electrolyte sheet.

  When forming an unsintered insulating sheet, first, butyral resin and dibutyl phthalate are added to ceramic powder mainly composed of alumina, and a mixed solvent (toluene and methyl ethyl ketone) is further mixed to produce a slurry. To do. The slurry is made into a sheet by a doctor blade method, and the mixed solvent is volatilized to produce an unfired insulating sheet.

  Furthermore, when forming an unsintered diffusion rate-determining part, first, a slurry in which 100% by mass of alumina powder, a heat-dissipated material (for example, carbon) and a plasticizer are dispersed by wet mixing is generated. The plasticizer has a butyral resin and DBP. Using this slurry, an unsintered diffusion rate controlling part is formed at a site that becomes the diffusion rate controlling part 95 and the ventilation part 99 after firing.

  Then, by pressing the uncompressed laminate at 1 MPa, a compacted compact 141 as shown in FIG. 6 is obtained. In addition, since it is the same as that of the manufacturing method of a well-known gas sensor element about the manufacturing method until it obtains the uncompressed laminated body before pressurization, detailed description is abbreviate | omitted.

  Then, the green body 141 obtained by pressurization is cut into a predetermined size, whereby a plurality of (for example, 10) unfired laminated layers whose sizes substantially match the element portions 71 and the heaters 73 of the gas sensor element 7. Get the body.

  Thereafter, the unfired laminate is removed from the resin, and further fired at a firing temperature of 1500 ° C. for 1 hour to obtain a fired laminate 143 as shown in FIG. This fired laminate 143 corresponds to the element body 70.

After obtaining the element body 70 in this manner, an unfired protective layer that becomes the protective layer 17 (see FIG. 2) after firing is formed around the tip side of the element body 70.
Thereafter, the unfired protective layer is heat-treated. Specifically, the element main body portion 70 on which the unfired protective layer is formed is heat-treated at a heat treatment temperature of 1000 ° C. and a heat treatment time of 3 hours to obtain the gas sensor element 7 on which the protective layer 17 is formed.

After obtaining the gas sensor element 7 in this way, an assembling step for assembling the gas sensor element 7 to the metal shell 5 is performed.
That is, in this step, the gas sensor element 7 produced by the above manufacturing method is inserted into the metal holder 51, and the gas sensor element 7 is fixed by the ceramic holder 41 and the talc ring 43, thereby producing an assembly. Thereafter, the assembly is fixed to the metal shell 5, and the rear end side of the gas sensor element 7 in the direction of the axis O is inserted into the talc ring 45 and the ceramic sleeve 9, and these are inserted into the metal shell 5.

Then, the ceramic sleeve 9 is caulked at the rear end portion 47 of the metallic shell 5 to produce a lower assembly. A protector 55 is attached to the lower assembly in advance.
On the other hand, the outer cylinder 57, the separator 13, the grommet 61, and the like are assembled to produce an upper assembly. Then, the lower assembly and the upper assembly are joined to obtain the air-fuel ratio sensor 1.

[1-5. Measurement test of insulation resistance between through holes]
A measurement test in which the insulation resistance between through holes in the gas sensor element 7 of the present invention is measured will be described.

  In this test, the rear end portion of the gas sensor element 7 (formation region of the electrode pads 25, 27, 29) was heated, and the insulation resistance between the three through holes 161, 162, 163 was measured. Specifically, three insulation resistances were measured: “between through-holes 161-163”, “between through-holes 163-162”, and “between through-holes 162-161”.

  In this measurement, two samples (first sample and second sample) were used as gas sensor elements. The dimension of “between through-holes 161-163” is 1.2 [mm], the dimension of “between through-holes 161-162” is 2.3 [mm], and “between through-holes 162-161”. The dimension of is 2.3 [mm].

FIG. 8 shows the test results of measuring the insulation resistance between the through holes.
According to the test results, each of the first sample and the second sample was tested between “between through-holes 161-163”, “between through-holes 163-162”, and “between through-holes 162-161”. In all the temperature bands (500 to 700 [° C.]), the insulation resistance shows a high value of 10 [MΩ] or more. In particular, in the case of 500 [° C.], the insulation resistance is 100 [MΩ] or more.

  In the conventional gas sensor element in which the through holes are formed in the solid electrolyte body, the insulation resistance between the through holes is 1.0 [MΩ in order to suppress the occurrence of leakage current (leakage current) between the through holes. The dimension between the through holes was set to be 4.8 [mm] or more so as to be above.

On the other hand, in the gas sensor element of the present invention, the insulation resistance between the through holes is 10 [MΩ] or more even when the dimension between the through holes is smaller than the conventional one.
For this reason, the gas sensor element of the present invention can reduce the dimension between the through holes as compared with the conventional gas sensor element in which the through holes are formed in the solid electrolyte body.

[1-6. effect]
As described above, in the gas sensor element 7 in the air-fuel ratio sensor 1 of the present embodiment, the electrode pad 25, the electrode pad 27, and the electrode pad 29 are connected to the through holes 163, 162, and 161 in the tip end region, respectively. Is formed. In other words, the plurality of through holes 163, 162, 161 are formed in the tip regions of the electrode pads 25, 27, 29 that are the connection destinations of the insulating substrate 97.

  In the gas sensor element 7 configured as described above, through holes 163, 162, 161 are formed in the tip region of the electrode pads 25, 27, 29, and the rear end of the electrode pads 25, 27, 29 in the longitudinal direction is formed. Through holes 163, 162, and 161 are not formed in the region and the central region. In addition, the electrode pad 25, 27, 29 has a portion other than the tip region (in other words, any one of the rear end region and the central region) occupies a large area. , 29 can be easily brought into contact with a portion other than the tip side region.

  Thus, since it becomes easy to take the structure which connects with the connection terminal 15 in locations other than a front-end | tip area | region among electrode pads 25, 27, and 29, the connection terminal 15 contacts the through holes 163, 162, and 161. It is possible to suppress the electrical connection between the connection terminal 15 and the electrode pads 25, 27, 29.

  Further, in the gas sensor element 7 configured in this way, in the assembly process with the connection terminal 15 connected to the electrode pads 25, 27, and 29, the connection terminal 15 is moved from the rear end side to the front end side of the outer surface of the gas sensor element 7. When moving (sliding), the connection terminal 15 does not move over the through holes 163, 162, 161.

  For this reason, it can suppress that a part of connection terminal 15 is caught in the through holes 163, 162, 161 and the connection terminal 15 is deformed, and the connection terminal 15 and the electrode pads 25, 27, 29 accompanying the deformation of the connection terminal 15 are prevented. Occurrence of poor electrical connection (abnormal disconnection) can be suppressed.

  Therefore, according to the air-fuel ratio sensor 1 including the gas sensor element 7, it is possible to suppress the occurrence of poor electrical connection between the electrode pads 25, 27, and 29 and the connection terminal 15. Further, according to the air-fuel ratio sensor 1 including the gas sensor element 7, it is possible to suppress the signal path of the sensor signal to the connection terminal 15 from being in an abnormal state.

  Further, the configuration in which the through hole 162 is formed in the tip end region of the electrode pad 27 is longer than the configuration in which the through hole 162 is formed in the rear end region of the electrode pad 27 in the length of the lead portion 79a of the oxygen concentration battery cell 81. Therefore, the amount of noble metal used for the lead portion 79a can be reduced. Thereby, the material cost in the gas sensor element 7 can be reduced, and the manufacturing cost of the gas sensor element 7 can be reduced.

  Next, in the gas sensor element 7, the electrode pad 25 and the electrode pad 27 are disposed via a gap Cw 1 in the width direction of the plate surface (first main surface 21) of the insulating substrate 97. The electrode pads 29 are arranged via a gap Cw2 in the width direction of the plate surface (first main surface 21) of the insulating substrate 97.

  With this configuration, when the connection terminal 15 is moved (slid) from the rear end side to the front end side of the outer surface of the gas sensor element 7 in the assembly process of the gas sensor element 7 and the connection terminal 15, the connection terminal 15, even if the electrode pads 25, 27, and 29 are cut and scraps are generated, short-circuit abnormality between the electrode pads 25, 27, and 29 is less likely to occur.

  That is, when the scraps of the electrode pads 25, 27, and 29 are generated, the movement direction of the scraps is the longitudinal direction of the first main surface 21 of the insulating substrate 97 that is the movement direction of the connection terminal 15 (the horizontal direction in FIG. 4). Thus, the range of movement of the first main surface 21 of the insulating substrate 97 in the width direction (vertical direction in FIG. 4) is small. Since the electrode pads 25, 27, and 29 are disposed with a gap in the width direction, it is difficult for the electrode pads 25, 27, and 29 to be electrically connected to each other due to the shavings. , 29 are electrically connected to each other, so that poor electrical connection (short circuit abnormality) is less likely to occur.

Therefore, according to the gas sensor element 7, it is possible to suppress the occurrence of poor electrical connection between the electrode pads 25, 27, 29 and the connection terminal 15.
Next, the electrode pads 25, 27, and 29 have the maximum width dimensions Wr 1, Wr 2, and Wr 3 in the rear end side regions from the center points of the through holes 163, 162, and 161, respectively. The shape is larger than the maximum width dimensions Wf1, Wf2, Wf3 of the tip side region from the point.

  Of the electrode pads 25, 27, and 29, the rear end region of the through holes 163, 162, and 161 is a contact region with the connection terminal 15, so that the maximum width dimensions Wr 1, Wr 2, and Wr 3 are large. The secured electrode pads 25, 27 and 29 are in good contact with the connection terminal 15.

  Thereby, according to the gas sensor element 7, generation | occurrence | production of the electrical connection defect of electrode pad 25,27,29 and the connection terminal 15 can be suppressed, and it suppresses that the signal path | route of the sensor signal with respect to the connection terminal 15 becomes an abnormal state. it can.

Next, in the gas sensor element 7, the distance between the plurality of through holes is 2.3 [mm].
By arranging a plurality of through holes in this way, the through hole formation region can be reduced, and the gas sensor element can be miniaturized.

  Further, as is clear from the test results shown in FIG. 8 described above, even if the distance between the plurality of through holes is set in this way, the occurrence of leakage current (leakage current) between the plurality of through holes is suppressed. it can.

  Therefore, according to the gas sensor element 7, it can suppress that leak current (leakage current) generate | occur | produces between several through holes, and can suppress that the signal path | route of the sensor signal with respect to the connecting terminal 15 will be in an abnormal state.

  The air-fuel ratio sensor 1 including such a gas sensor element 7 can suppress the occurrence of poor electrical connection between the electrode pads 25, 27, 29 and the connection terminal 15, and the sensor for the connection terminal 15 from the electrode pad portion of the gas detection element. It can suppress that the signal path of a signal will be in an abnormal state.

[1-7. Correspondence with Claims]
Here, the correspondence of the words in the claims and the present embodiment will be described.
The air-fuel ratio sensor 1 corresponds to an example of a gas sensor, each of the oxygen concentration battery cell 81 and the oxygen pump cell 89 corresponds to an example of a cell (embedded cell), the insulating substrate 97 corresponds to an example of an insulating substrate, and an electrode pad 25, 27, and 29 correspond to an example of a plurality of electrode pad portions. The through holes 165, 166, and 176 each correspond to an example of a first through hole, and the through holes 161, 162, and 163 each correspond to an example of a second through hole.

The through hole 76a corresponds to an example of a hollow portion, the insulating member 76 corresponds to an example of a frame member, the through hole 84a corresponds to an example of a hollow portion, and the insulating member 84 corresponds to an example of a frame member.
The porous electrodes 77 and 79 correspond to an example of a pair of electrode portions, the porous electrodes 85 and 87 correspond to an example of a pair of electrode portions, the lead portions 77a and 79a correspond to an example of a pair of lead portions, The lead portions 85a and 87a correspond to an example of a pair of lead portions.

[2. Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it is possible to implement in various aspects.

  For example, in the above-described embodiment, with respect to the arrangement of the electrode pads 25 and 29 and the electrode pad 27, there is no gap in the longitudinal direction of the plate surface (first main surface 21) of the insulating substrate 97. The arrangement configuration is not limited to this.

  Specifically, like the gas sensor element of the second embodiment shown in FIG. 9, the electrode pads 25, 29 and the electrode pad 27 are gaps in the longitudinal direction of the plate surface (first main surface 21) of the insulating substrate 97. The structure arrange | positioned via Cd1 can be taken.

  As described above, the electrode pads 25 and 29 and the electrode pad 27 are arranged with the gap Cd1 in the longitudinal direction therebetween, so that the distance between the electrode pad 25 and the electrode pad 27 and the electrode pad 29 and the electrode pad 27 are A large distance can be secured. As a result, the plurality of electrode pads 25, 27, 29 are arranged at a distance from each other. Connection failure (short circuit abnormality) is less likely to occur.

  Further, when the plurality of electrode pads 25, 27, 29 are arranged via the gaps Cw1, Cw2 in the width direction and the gap Cd1 in the longitudinal direction, the plurality of electrode pads 25, 27, 29 are even more Since the distance between the electrode pads 25, 27 and 29 becomes conductive, poor electrical connection (short circuit abnormality) is less likely to occur.

  Therefore, according to the gas sensor including the gas sensor element having such a configuration, electrical connection failure (short circuit abnormality) due to conduction between the plurality of electrode pads 25, 27, and 29 is unlikely to occur.

  Next, regarding the arrangement of the electrode pads 25, 27, and 29, an overlapping region may exist in the longitudinal direction of the plate surface (first main surface 21) of the insulating substrate 97. Specifically, like the gas sensor element of the third embodiment shown in FIG. 10, the electrode pads 25 and 29 and the electrode pad 27 overlap in the longitudinal direction of the plate surface (first main surface 21) of the insulating substrate 97. An arrangement configuration having regions can be adopted.

  In such a configuration, the shape of the electrode pad 25 and the electrode pad 29 may be a shape having the defect portion 25a and the defect portion 29a in the rear end region, respectively. As a result, a large distance between the electrode pads 25 and 29 and the electrode pad 27 can be secured, and the occurrence of leakage current (leakage current) between the electrode pads can be suppressed.

  Therefore, according to the gas sensor including the gas sensor element having such a configuration, electrical connection failure (short circuit abnormality) due to conduction between the plurality of electrode pads 25, 27, and 29 is unlikely to occur.

  DESCRIPTION OF SYMBOLS 1 ... Air-fuel ratio sensor, 5 ... Metal fitting, 7 ... Gas sensor element, 15 ... Connection terminal, 25 ... Electrode pad, 25a ... Defect part, 27 ... Electrode pad, 29 ... Electrode pad, 29a ... Defect part, 75 ... Solid electrolyte , 76 ... insulating member, 76a ... through-hole, 77 ... porous electrode, 77a ... lead portion, 79 ... porous electrode, 79a ... lead portion, 81 ... oxygen concentration battery cell, 83 ... solid electrolyte body, 84 ... insulation Member 84a ... through hole 85 ... porous electrode 85a ... lead portion 87 ... porous electrode 87a ... lead portion 89 ... oxygen pump cell 97 ... insulating substrate 161 ... through hole 162 ... through hole 163 ... through hole, 165 ... through hole, 166 ... through hole, 171 ... through hole, 172 ... through hole, 176 ... through hole.

Claims (5)

A frame having a plurality of first through holes which are made of a plate-shaped insulating material extending in the longitudinal direction, have a hollow portion on the front end side, and penetrate through in the thickness direction on the rear end side and have conductors disposed therein. A member, a solid electrolyte body disposed in the hollow part, a pair of electrode parts formed on an outer surface of the solid electrolyte body, and connected to the electrode part and the first through hole and extending in the longitudinal direction A cell comprising a pair of lead portions;
A plurality of plate-shaped insulating materials laminated on the cell, and a conductor is disposed inside the rear end side in the thickness direction and communicated with the plurality of first through holes. An insulating substrate having a second through hole;
A plurality of electrode pad portions connected to the plurality of second through holes disposed on the outer surface of the insulating substrate, and a gas sensor element,
A plurality of connection terminals connected to the electrode pad portion;
A metal shell for holding the gas sensor element in a state where the connection terminal is connected to the electrode pad portion;
A gas sensor for detecting a specific gas component in the measurement target gas,
The plurality of second through holes are formed in a tip region of the electrode pad portion to be a connection destination of each of the insulating substrates.
A gas sensor. A plurality of the electrode pad portions are arranged via gaps in the width direction of the plate surface of the insulating substrate;
The gas sensor according to claim 1. A plurality of the electrode pad portions are disposed via gaps in the longitudinal direction of the plate surface of the insulating substrate;
The gas sensor according to claim 1 or 2, wherein: The distance between the plurality of first through holes is 2.3 [mm] or less,
The gas sensor according to any one of claims 1 to 3, wherein: The electrode pad portion has a shape in which the maximum width dimension of the rear end side region from the center point of the second through hole is larger than the maximum width dimension of the tip side region from the center point of the second through hole. ,
The gas sensor according to any one of claims 1 to 4, wherein: